Tunable interdot coupling in few-electron bilayer graphene double quantum dots

TL;DR

This paper demonstrates a bilayer graphene double quantum dot device with tunable interdot tunnel coupling and capacitive coupling, enabling precise control for quantum computing applications.

Contribution

It introduces a device architecture allowing independent tuning of tunnel and capacitive couplings in bilayer graphene quantum dots.

Findings

Interdot tunnel coupling tunable from 1 to 4 GHz

Mutual capacitive coupling adjustable between 0.2 and 0.6 meV

Charging energy remains nearly constant

Abstract

We present a highly controllable double quantum dot device based on bilayer graphene. Using a device architecture of interdigitated gate fingers, we can control the interdot tunnel coupling between 1 to 4 GHz and the mutual capacitive coupling between 0.2 and 0.6 meV, independently of the charge occupation of the quantum dots. The charging energy and hence the dot size remains nearly unchanged. The tuning range of the tunnel coupling covers the operating regime of typical silicon and GaAs spin qubit devices.